Development of emission factors for ships’ emissions at berth

As shipping transportation is growing continuously, ship exhaust emissions are expected to rise, resulting in increased risks to both ecology and human health. In order to examine these risks and the potential benefits of control measures, ship exhaust emissions need to be quantified. However, precise measurement and collection of emission data is challenging due to numerous factors including diversity of engine types and configurations, various operation modes and the mobility of ships. Due to restrictions imposed for on-board measurements, emission inventories are commonly estimated shipping emissions. This method suffers from lack of updated and detailed emission factors (EFs). Results are therefore inconsistent for emission predictions, especially in near-shore areas. Thus, there is a clear need for investigation to improve the accuracy of these estimates. In this study, on-board measurement was carried out on Medium Speed Diesel (MSD) Auxiliary Engines (AEs) at berth. Both cargo vessels ran on heavy fuel oil (HFO). Measurements for gaseous emissions were carried quantifying CO, CO2, SOx and NOx. In this study, a new set of EF equations are developed to help improving the emission estimation models. To develop the equations, non-linear regression analysis was used. The predicted emissions were compared with current inventories and on-board measurements from two diesel engines. The results for emissions showed closer agreement with the on-board measurement and an improvement in prediction accuracy of emissions compared with existing inventories.